NVIDIA's GeForce 7800 GTX Hits The Ground Running
by Derek Wilson on June 22, 2005 9:00 AM EST- Posted in
- GPUs
No More Memory Bandwidth
Again, we have a 256 bit (4x 64 bit) memory interface to GDDR3 memory. The local graphics memory setup is not significantly different from the 6800 series of cards and only runs slightly faster at a 1.2 GHz effective data rate. This will work out in NVIDIA's favor as long as newer games continue to put a heavier burden on pixel shader processing. NVIDIA sees texture bandwidth as outweighing color and z bandwidth in the not too distant future. This doesn't mean the quest after ever increasing bandwidth will stop; it just means that the reasons we will need more bandwidth will change.A good example of the changing needs of graphics cards is Half-Life 2. While the game runs very well even on older graphics cards like the 9800 Pro, the design is such that increased memory bandwidth is far less important than having more shader processing power. This is why we see the 6600GT cards significantly outperform the 9800 Pro. Even more interesting is that in our testing, we found that enabling 4xAA on a 9800 Pro didn't affect performance of HL2 much at all, while increasing the resolution from 1024x768 to 1280x1024 had a substantial impact on frame rates. If the HL2 model is a good example of the future of 3D engines, NVIDIA's decision to increase pixel processing power while leaving memory bandwidth for the future makes a lot of sense.
On an interesting side note, the performance tests in this article are mostly based around 1600x1200 and higher resolutions. Memory usage at 2048x1536 with 32bit color and z-buffer runs a solid 144MB for double buffered rendering with 4x AA. This makes a 256MB card a prerequisite for this setup, but depending on the textures, render targets and other local memory usage, 256MB may be a little short. PCI Express helps a little to alleviate any burden placed on system memory, but it is conceivable that some games could get choppier when swapping in and out large textures, normal maps, and the like.
We don't feel that ATI's 512MB X850 really brings anything necessary to the table, but with this generation we could start to see a real use for 512MB of local memory. MRTs, larger textures, normal maps, vertex textures, huge resolutions, and a lack of hardware compression for fp16 and fp32 textures all mean that we are on the verge of seeing games push memory usage way up. Processing these huge stores of data require GPUs powerful enough to utilize them efficiently. The G70 begins to offer that kind of power. For the majority of today's games, we are fine with 256MB of RAM, but moving into the future it's easy to see how more would help.
In addition to these issues, a 512MB card would be a wonderful fit for Dual-Link DVI. This would make the part a nice companion to Apple's largest Cinema Display (which is currently beyond the maximum resolution supported by the GeForce 7800 GTX). In case anyone is curious, a double buffered 4xAA 32bit color+z framebuffer at 2560x1600 is about 190MB.
In our briefings on G70, we were told that every part of the chip has been at least slightly updated from NV4x, but the general architecture and feature set is the same. There have been a couple of more significant updates as well, namely the increased performance capability of a single shader pipe and the addition of transparency antialiasing. Let's take a look at these factors right now.
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VIAN - Wednesday, June 22, 2005 - link
"NVIDIA sees texture bandwidth as outweighing color and z bandwidth in the not too distant future." That was a quote from the article after saying that Nvidia was focusing less on Memory Bandwidth.Do these two statements not match or is there something I'm not aware of.
obeseotron - Wednesday, June 22, 2005 - link
These benchmarks are pretty clearly rushed out and wrong, or at least improperly attributed to the wrong hardware. SLI 6800 show up faster than SLI 7800's in many benchmarks, in some cases much more than doubling single 6800 scores. I understand NDAs suck with the limited amount of time to produce a review, but I'd rather it have not been posted until the afternoon than ignore the benchmarks section.IronChefMoto - Wednesday, June 22, 2005 - link
#28 -- Mlittl3 can't pronounce Penske or terran properly, and he's giving out grammar advice? Sad. ;)SDA - Wednesday, June 22, 2005 - link
QUESTIONOkay, allcaps=obnoxious. But I do have a question. How was system power consumption measured? That is, was the draw of the computer at the wall measured, or was the draw on the PSU measured? In other words, did you measure how much power the PSU drew from the wall or how much power the components drew from the PSU?
Aikouka - Wednesday, June 22, 2005 - link
Wow, I'm simply amazed. I said to someone as soon as I saw this "Wow, now I feel bad that I just bought a 6800GT ... but at least they won't be available for 1 or 2 months." Then I look and see that retailers already have them! I was shocked to say the least.RyDogg1 - Wednesday, June 22, 2005 - link
But my question was "who," was buying them. I'm a hardware goon as much as the next guy, but everyone knows that in 6-12 months, the next gen is out and price is lower on these. I mean the benches are presenting comparisons with cards that according to the article are close to a year old. Obviously some sucker lays down the cash because the "premium," price is way too high for a common consumer.Maybe this one of the factors that will lead to the Xbox360/PS3 becoming the new gaming standard as opposed to the Video Card market pushing the envelope.
geekfool - Wednesday, June 22, 2005 - link
What no Crossfire benchies? I guess they didn't wany Nvidia to loose on their big launch day.Lonyo - Wednesday, June 22, 2005 - link
The initial 6800U's cost lots because of price gouging.They were in very limited supply, so people hiked up the prices.
The MSRP of these cards is $600, and they are available.
MSRP of the 6800U's was $500, the sellers then inflated prices.
Lifted - Wednesday, June 22, 2005 - link
#24: In the Wolfenstein graph they obviously reversed the 7800 GTX SLI with the Radeon.They only reveresed a couple of labels here and there, chill out. It's still VERY OBVIOUS which card is which just by looking at the performance!
WAKE UP SLEEPY HEADS.
mlittl3 - Wednesday, June 22, 2005 - link
Derek,I know this article must have been rushed out but it needs EXTREME proofreading. As many have said in the other comments above, the results need to be carefully gone over to get the right numbers in the right place.
There is no way that the ATI card can go from just under 75 fps at 1600x1200 to over 100 fps at 2048x1535 in Enemy Territory.
Also, the Final Words heading is part of the paragraph text instead of a bold heading above it.
There are other grammatical errors too but those aren't as important as the erroneous data. Plus, a little analysis of each of the benchmark results for each game would be nice but not necessary.
Please go over each graph and make sure the numbers are right.